Saturday, April 21, 2007

Is goodness natural or influenced by kinship and reciprocity?This article discusses one of the dilemmas Darwin faced when defending his theory of evolution: why do animals commit the ultimate act of goodness - sacrificing themselves for others - if their main motivation in life is to pass on their genes to the next generation? Darwin realized that in most such cases, such sacrifice is done for blood relatives, and actually does indirectly help pass one's genes on. However, there are other factors involved. In the 1960s, a biologist named William Hamilton figured out a mathematical formula to explain altruism. In this formula, r is relatedness to the potential recipient of kindness, c is cost of helping them, and b is what the altruistic individual gains from being altruistic. If r X b > c, altruism is worth it. While I have no idea how anyone actually can determine exactly what r, b, and c are, this is an interesting extension of evolutionary biology.

The article loads very slowly, so I am including the text at the end of this post.

Here is another interesting article: PBS’ ‘Nature’ exploring the evolution of man’s best friend It describes an episode of the show "Nature" that explains how dogs evolved. In the Mesolithic era 15,000 years ago, people began living in villages, and dogs, descended from wolves, appeared around this time. It is unlikely that people domesticated wolves because they would have to be domesticated at the age of 13 days or younger. The new theory on the subject is that when human villages formed, nearby wolves discovered that they could eat from the garbage the humans created rather than hunting. Wolves who were naturally more tame would have adapted to this lifestyle more easily than others, and others would have left or died. Tame wolves reproduced with other tame wolves, and over time populations of wolves near villages became more tame. Humans responded to the tame wolves, and they became our pets. I find this interesting because if true, it indicates that on some level, we did not domesticate dogs, but dogs domesticated us.

It is hard to imagine that anyone thinks of goodness as a problem, but evolution pioneer Charles Darwin did. The little worker bees that sacrificed themselves to protect their hives -- the ultimate example of animal goodness -- kept Darwin up at night.

If Darwin's ideas about evolution and natural selection were correct -- and, of course, they are -- then this sort of altruism should be extraordinarily rare in nature. If increased reproduction is the ultimate end all and be all of evolution by natural selection, then altruists should disappear -- and fast.

But they don't disappear, and Darwin was so puzzled by this that he spoke of altruism as a problem that could prove fatal to his whole theory of evolution.

Then a solution to this nasty conundrum hit Darwin like a ton of bricks. Worker bees weren't helping just any old bunch of bees, they were protecting their hive. And their hive contained special individuals: blood relatives.

Blood relatives are, by definition, very similar to one another. So even though the little worker bees may have been giving up their lives, by doing so they were potentially saving hundreds of blood relatives. In modern parlance, we'd say that the worker bees were helping blood kin, because blood kin are genetically related. By helping your blood relatives, you are indirectly promoting the reproduction of copies of your own genes -- copies that just happen to reside inside your kin.

Darwin wasn't the only scientist who was fascinated with the question of the evolution of goodness. His good friend and colleague, Thomas Henry Huxley, was as well. Huxley got himself into a heated argument over whether blood kinship could or could not explain altruism.

Huxley's opponent was Prince Peter Kropotkin, ex-page to the Czar of Russia, naturalist and arguably the most famous anarchist of the 19th century. Huxley argued that all goodness could be traced to blood kinship, while Kropotkin argued that goodness and blood kinship were completely divorced from one another.

Neither was right, as it turned out, but it would take almost a hundred years before a shy, reserved and brilliant British biologist named William Hamilton would settle all the arguments about blood kinship and altruism by coming up with a simple, but elegant mathematical equation.

Instead of asking whether blood kinship is the single factor explaining altruism, Hamilton approached the question from a different perspective. He began by defining three terms: the genetic relatedness between individuals (labeled r), the cost of an act of goodness (c), and the benefit that a recipient obtained when someone was nice to him or her (b). Using some beautiful mathematics, in the early 1960s Hamilton discovered that altruism and blood kinship are not linked by an all-or-nothing relationship.

Instead, what is now known as "Hamilton's Rule" states that altruism evolves whenever r times b is greater than c. In other words, if enough relatives receive benefits from altruism to outweigh the cost of altruism, then altruism spreads; otherwise, it does not.

Phrased in the cold language of natural selection, blood relatives are worth helping in direct proportion to their genetic (blood) relatedness, weighted by how great a benefit they received.

Literally thousands of experiments with both nonhumans and humans show the power of Hamilton's Rule. This little equation is evolutionary biology's version of E = mc2.

Over and over, we see that an analysis of the costs and benefits of altruism, along with the genetic relatedness of interactants, allows us to predict the presence or absence of altruism.

Hamilton's Rule, of course, does not explain all altruism. Another large chunk of goodness falls under the category of "reciprocity." Individuals are sometimes willing to be altruistic to someone now in the expectation that they will, in turn, be helped when we they need it.

Evolutionary biologists have been almost as interested in this type of altruism, as they have been in kinship-based altruism. Amazingly enough, it was Hamilton, along with the political scientist Robert Axelrod and the evolutionary biologist Robert Trivers, who formalized the models behind the evolution of reciprocity.

Following up on work done by Trivers in the early 1970s, in 1981, Axelrod and Hamilton used the mathematics of game theory to predict when so-called "reciprocal altruism" should evolve. Again, scores of empirical studies have followed up the model.

Reciprocity can be complex, but an evolutionary perspective has cleared the path to understanding, just the same way it did in the case of blood kinship and altruism.

If goodness is a problem, then the answer -- or at the least part of the answer -- can be found in evolutionary biology.

Lee Alan Dugatkin is a professor of biology and distinguished university academic in the biology department at the University of Louisville in Kentucky.

Wednesday, April 18, 2007

Cladism is all about branching: structures like evolutionary history, the folders on your computer, and family trees have properties in common that can be measured in interesting ways.

One advantage to evolution is that it has restrictions on the branching. Fruit trees can be grafted and I won't even go into the complexities that can develop in some family trees! Bacteria–and even more complex species that have not been isolated so long that they can no longer breed–can complicated things if you are trying to measure relatedness or inheritance. BUT there are no jackelopes, not even batmen.

Compare natural evolution to cultural evolution and this difference is obvious. In culture we have an abundance of batmen! Branches combine and recombine, in a flagrant promiscuity that puts rhizomes and spores and algae to shame. Nonetheless there is a long history of efforts to determine inheritance. We care where things originated. Just think of your English teacher reminding you that Shakespeare said it first or your friend insisting "that wasn't Rod Stewart but Tom Waits' song" and you counter "that wasn't Tom Waits but a Louisiana funeral march" and another "that wasn't a Louisiana funeral march but an 18th C French folktale..."

For this reason its hard to know what cultural evolution even means. Dawkins' coined the word memes to refer to reproducible cultural units, on the analogy to genes, but because of the aforementioned restrictions that obtain in natural evolution, its a pretty sloppy concept. Lets take another cultural example. (I may get this wrong at one point but) the word Buxom originally came from a Scottish word for wheat, and was already a metaphor in its common usage. To say you were buxom, was to say that you bent easily, like wheat in the wind, to moral temptation. The word was frequently applied to women deemed loose in their morals. With time it became more associated with these women than the wheat of the metaphor, and eventually settled on the anatomy these allegedly loose women were famous for...What a rate of mutation!

So: in order to think about cultural evolution I think it is useful to go back to one of the historical questions about evolution: Use and Disuse. Charles Darwin did not completely dismiss this "Lamarckian" factor in a few of his works, and it was the backbone of his grandfather Erasmus Darwin's earlier evolutionary theory.

How would species branch differently if they evolved by passing on to their offspring the traits (muscles, minds, etc.) that were developed by use and disuse during their lifetime?

Here are some links to sites which attempt to map evolving systems, both natural and cultural (and perhaps some in between) Have a look if you see this before I come to class tonight (Wednesday 18 at 8:00):

My new and hot article this week is from the London Daily Telegraph, which reports that Darwin's famed Galapagos Islands are in the midst of such a huge "institutional, environmental, and social crisis" that ecotourism is being suspended. Apparently, the over 120,000 visitors per year-- and the airports, illegal fishing, and parasites they bring with them-- to the archipelago have introduced some serious problems, potentially harming the giant tortoises, 13 different species of finches, and marine iguanas (among so many other species) that live there. Officials worry that the ecosystem that helped inspire Darwin's theories is too fragile to hold up to the pressure. I felt that this article ties in well with what we've been talking about regarding the importance of place to historical events; how much of a role did the Galapagos Islands play in the formation of the theory? Similarly, how did all the other places where Darwin lived and worked affect his ideas? We will find out...

Full article at http://washingtontimes.com/world/20070416-103350-4771r_page2.htm

A recent article from BBC news discusses recent controversy over the connection between the extinction of the dinosaurs and the rapid proliferation of mammals. The established paradigm today suggests that when the dinosaurs disappeared at the end of the Cretaceous period, mammals flourished and subsequently diverged into different subgroups. Under this theory, the asteroid that hit the earth and caused the mass extinction of the dinosaurs provided the opportunity and space and resources for mammals to proliferate, previously impossible due to the dominance of the dinosaurs. However, new evidence arising from new technology has led to different conclusions. Dr. Kate Jones from the Zoological Society in London describes the new technology: “The supertree is a new way of showing all the mammal species on the planet, starting with a common ancestor”. The new technology allows the synthesis of “already published information from hundreds of researchers around the world”. After the technology gathers the data, computers “recode” and analyze the information to combine it into a “supertree”. The evidence from this new “supertree suggests that placental mammals had already split into major subgroups well before the disappearance of the dinosaurs. Additional research suggests that the correlation between the extinction of the dinosaurs and the growth of mammal species is not clear-cut. According to research there was a “several million year” period over which the changes occurred. Today as scientists continue to gather fossil evidence, we can access a more and more accurate picture of our history. The fact that we are still working out and developing new theories relating to evolution is yet another example of the significance of Darwin’s revolutionary impact on science. I found this article particularly interesting in relation to Darwin because, just as Darwin overturned an established paradigm by synthesizing material and evidence from diverse strands of science, this new computerized technology has done the exact same thing with worldwide data.

To read more the link is: http://newsvote.bbc.uk/mpapps/pagetools/print/news.bbc.co/uk/2/hi/science/nature/6503045.stm

Tuesday, April 17, 2007

The next time you start to complain about your lackluster love life, stop yourself and count your blessings. While you may be going through a dry spell, the bdelloid rotifer hasn't had sex in over forty million years! Let's just say that its frustrations are a little more serious than whatever problems you're currently experiencing. The bdelloid rotifer has it so bad that until recently, most scientists would have considered such a lack of sexual activity to be more than just a source of angst for the rotifer on weekend nights, as sexual selection has long been considered essential for the formation of new species through natural selection.

Recent studies of the bdelloid rotifer conducted at Imperial College in London, however, have proved that this idea is not supported by empirical evidence. While previously it was thought that asexual species should eventually become extinct because they cannot perform natural selection fast enough to adapt to environmental changes, the bdelloid rotifer has existed for millions of years, and recent DNA testing has also revealed that there are several distinct species of bdelloid rotifer that have formed without sexual selection.

The researchers reporting these findings call them "groundbreaking" in that findings such as this suggest that there is still much to learn about the basic mechanisms of evolution. Studies such as this call into question some of the central tenets of evolutionary theory. If sex isn't really essential to evolutionary divergence as once thought, then what else about Darwinian theory that we currently accept as undeniably true in theory might someday be proved wrong by experimental evidence?

According to a study performed at the University of Michigan and published in the journal of the Proceedings of the National Academy of Sciences, it appears that chimpanzees possess more genes that show signs of ‘positive selection,’ or quick evolution because of an adaptive benefit in the environment. By this method of genetic evaluation, the article claims that chimpanzees have essentially evolved further than humans have from our common ancestor. This raises many interesting questions regarding the reasons for evolutionary mutations and the idea that “more intelligent species are ‘more evolved’.” The claims made by this article also call into question the effects that human society and technology have had on human evolution throughout mankind's recorded history.

“In the study, which is published in the journal Proceedings of the National Academy of Sciences, the researchers compared 14,000 human and chimp genes to see how they had been affected by evolution since the split. They particularly looked for genes that showed evidence of positive selection — those that had evolved quickly because of an adaptive benefit in the environment — rather than those that had changed more slowly by random genetic drift. They found 154 human genes that showed evidence of the rapid positive selection that marks out adaptive traits, but 233 chimp genes with the same qualities.”

"Profile of Chimpanzee" from Richard Lydekker's 1893 Royal Natural History. Vol. 1(via Wikimedia).

In the same vein as Kate's new and hot, a recent article in the New York Times titled "Almost Human, and Sometimes Smarter" discusses Chimpanzee culture, behavior, and cognition.

Based on a March conference called "Mind of the Chimpanzee," the article (and the conference) revolve around the consensus that chimps have emotions and culture. I'm not sure that chimp culture is as universally accepted as the NYT article makes it seem (this is hotly debated by prominent anthropologists), but behavioral research on chimps has some pretty profound evolutionary implications.

If chimps show precursors to behaviors that are prototypically human, like tool use, then this is a way to think about the development of human culture and behavior: "Their behavior and intelligence, scientists say, may offer insights into the abilities of early human ancestors like Australopithecus afarensis, the apelike 'Lucy' species that thrived more than three million years ago. A more urgent motivation for the research, primatologists say, is that these are sentient beings and the closest living relatives of humans, and their survival is threatened."

A far greater implication unmentioned in the article is that if humans evolved our reliance on culture, and consequently our vast cultural variability, then the bright line difference that many people perceive between humans and animals becomes significantly grayer. The growing evidence for a link between humans, our closest evolutionary relatives, and other animals should be used to make a moral argument for species protection, but it must also be used as evidence for the very real evolutionary history of our species.

If humans are not distinct from apes and lie with them on an evolutionary gradient of derived traits, perhaps our heightened awareness of our place in our evolutionary lineage may lead to a greater humility on the part of our species. Our ancestors could have easily taken a different path, and we too could have evolved to be incredibly chimp-like, sitting in the forest using rocks to open nuts. What's important, though, is that there's nothing wrong with that -- we're not the end product of evolution. Chimpanzees are still here too; in many ways, their continued existence makes them as much of an evolutionary success as we are.

I spotted this hand-made sticker on the blue emergency pole outside of the Stanford Post Office.

Here's my new and hot- it's an answer to those people that will not believe evolution because there is no record of all the transitional phases between humans and single-celled organisms. It talks about how if you had a photo album of all your ancestors, it would likely have some photos missing, and some in really poor condition, but that doesn't mean some of your ancestors didn't have parents...

http://www.bbc.co.uk/dna/h2g2/A4351628

Here's my review of Darwin's autobiography. It's on Amazon's site for the Autobiography of Charles Darwin 1809-1882, edited by Nora Barlow:

I know someone has already posted something about chimps, but here's a different article about them, from the New York Times: http://www.nytimes.com/2007/04/17/science/17chimp.html?ref=science, "Almost Human, and Sometimes Smarter." It's about how similar we are to chimps, our relative from whom we diverged only about 4-6 million years ago. We share all but 1.23% of our genes with them. The article talks about how several traits that we think of as distinctly human are actually shared by our primate relatives. Chimps use tools, and teach their children how to use them. Such socially transmitted behavior is demonstrative of culture. Chimps also show empathy and coorperation. They also have better short-term memory than humans, though our long-term memory beats theirs. I know in Darwin's Descent of Man, he spends a lot of time trying to convince his readers that we are not so different from other animals, and thus could have evolved from them without needed impossibly large leaps. I guess modern science is proving that right...

Monday, April 16, 2007

A New Religious Editorial, Classic TacticsAs I was searching for this week's new and hot, I came upon a recently written editorial from The Conservative Voice here . Written by Babu Ranganathan, a graduate of Bob Jones University, I thought this editorial arguing for intelligent design used some of the techniques of misdirection and use of convincing but illogical rhetoric that we talked about last week. For instance, Mr. Ranganathan craftily uses the fact that science cannot explain the origin of life to argue for intelligent design - the tactic of poking a hole in scientific theory as a means to bolster support for the existence of a designer.

ALSO - The Galapagos Islands are in trouble!

Following is the first part of the article from The Washington Times found here .

They inspired Charles Darwin, harbor the most stunning menagerie, and delight thousands of tourists each year.

But the Galapagos Islands were put off limits Wednesday because of fears that their fragile ecosystem is close to collapse.

The islands that inspired Darwin's theories on evolution are at grave risk from a population boom, overfishing and, the Ecuadoran government says, the thousands who travel each year to see the remarkable animals that live there.

The Pacific islands about 600 miles west of Ecuador harbor centenarian giant tortoises, blue-footed boobies, marine iguanas and even vampire finches.

These creatures may no longer be on the itineraries of ecotourists after Ecuadoran President Rafael Correa signed a decree to suspend tourism and preserve the islands' natural treasures.

"We are pushing for a series of actions to overcome the huge institutional, environmental and social crisis in the islands," said Mr. Correa, pre-empting the findings of a United Nations Environmental, Scientific and Cultural Organization report on the archipelago. Mr Correa said the required course of action is clear. "We do not need studies from some international organization," he said. "We are declaring the Galapagos at risk."

The government measures also would include a census of the islands, home to a significant illegal human population.

UNESCO declared the islands a world heritage site in 1971 and has monitored the ecosystem.

Though authorities cap the number of tourists, the islands have about 120,000 visitors each year, 100,000 more than 30 years ago. Mr. Correa said Ecuador will consider suspending some tourism permits and enforce rigorous population restrictions. The indigenous species have long struggled to contend with the arrival of nonnative predators such as black rats, dogs, cockroaches and cats that have been introduced since English pirates brought goats in the 18th century.

Environmental pressures have increased in recent years, including a growing human population, illegal fishing of sharks and sea cucumbers, as well as internal bickering at the islands' national park. UNESCO's World Heritage Center warned last month of the threats to the islands' flora and fauna. A U.N. delegation is visiting the islands to determine whether the world heritage site should be officially declared in danger.

Critics say the Ecuadoran government failed to act as environmental pressures built on its main tourist attraction.

David Sloan Wilson, an evolutionist and professor at Binghampton University, is a strong proponent of the idea of multilevel selection theory. Multilevel selection has been used to rectify limitations of earlier group selection models. This new theory suggests that while genes are provide the information that is passed on, it is individuals (the vehicles for genes) and how they interact in a group that determines which genes are passed on and which die out. In particular, this theory offers an explanation behind group altruism.

A few weeks ago, Professor Wilson published a book entitled Evolution for Everyone: How Darwin's Theory Can Change the Way We Think About Our Lives, in which he attempts to find evolution in our daily lives and its real-world implications. Professor Wilson also heads the Evolution Studies Program at Binghampton University, which allows students to study evolution in relation to any other field. More information about this program can be found at http://bingweb.binghamton.edu/~evos/.

I tripped across a cool pair of news articles on Yahoo, both re-emphasizing the connection between humans and primates. The first one is about the genetic similarity between humans and macaque monkeys, and the second is about cave-dwelling chimps. Apparently, the macaque's DNA map provided a lot of useful information about what makes humans "human" (according to the article, we share 93% of our genetic make-up with macaques and 98% with chimpanzees). What is really interesting is that macaques suffer from a disease called simian immunodeficiency virus (SIV) which is very similar to AIDS, and are widely used in the testing of new HIV drugs and treatments. Click here to read to the full article.

The article about chimps is more cultural and less biological I suppose. Chimps at a field site in Africa have been observed making use of caves for shelter against the heat, much like early humans. This article can be accessed here.

Click here for an article that was pretty big in the science news about 2 months ago. I guess it was sort of interesting that in class we talked about about how 3 generations of Darwins married Wedgewoods and all this incest was pretty sketchy...

Also I guess this sort of stuff happened back in the old days when royalty would marry other royalty to keep the wealth within the family.

Long story short, this inbreeding is not really a good call. However, that article found that in the animal world, it looks like inbreeding happens sometimes with many more benefits than harms. The logic and analysis they give is certainly interesting.

Sunday, April 15, 2007

So basically, this is awesome! I'm surprised no one has jumped on this.

The name of the article is "T-Rex tissue offers evolution insights." Some scientists found T-Rex bones on the side of a cliff in Montana that still had some soft tissues attached. Mary Schweitzer, a paleontologist at North Carolina State University, put the tissue under an electron microscope, and the material looked identical to blood vessels in modern ostrich bones. Studying this tissue is giving evolutionary insights into how dinosaurs are related to creatures of today. Schweitzer found 3 amino acid sequences identical to sequences found in chicken DNA, providing evidence for the idea that birds and dinos are relatives, an idea that had already been postulated by scientists. Sequences were found matching several other animals as well, including a newt and a frog.

I think its pretty amazing that perfect geological and environmental conditions have preserved this stuff for 68 million years. It's pretty cool for Schweitzer too, who had been insisting for years that this sort of preserved tissue could exist, while her colleagues laughed at her.

Anyway, I encourage everyone to go read the article. It's about dinosaurs, how could it not be awesome?

New York Times “Broadway Revival Reflects U.S. Debate on Evolution” – April 15, 2007

Debuted in 1955, “Inherit The Wind” is a Broadway play that dramatizes the 1925 Scopes Trial (also known as the “monkey trial”). More than fifty years later, this play, written by Jerome Lawrence and Robert Lee, has been revived with continuing relevance. The play’s director, Doug Hughes, commented, “The idea that 50 or more years later there is more controversy about its teaching than there may have been in ’55…is amazing.” Hughes also highlighted how the evolution debate is a uniquely American issue. He said, “Fundamental belief seems to be very important to us in America. We are among the most religious countries on earth… And yet our democracy is founded on an extremely secular document, the United States Constitution, and therein lies the paradox -- how do you square those two things?” I agree that it is remarkable that the debate is more heated now than in the past. One would think that as time went on and more scientific proof of evolution was discovered that the debate would lose its steam. It would be interesting to examine the current audience composition, audience response and overall popularity of the play and compare with that of the past.